1. Field of the Invention
This invention relates to electric lamps and has particular reference to an improved halogen incandescent lamp for general lighting and vehicular lighting purposes.
2. Description of the Prior Art
Incandescent lamps that contain a tungsten filament and a halogen atmosphere which coact during lamp operation to provide a regenerative cycle that returns vaporized tungsten back to the filament are well known in the art. An iodine-dosed lamp of this type is described in U.S. Pat. No. 2,883,571 issued to Fridrich et al. An incandescent projection lamp having an envelope that is composed of borosilicate glass and contains a halogen additive is disclosed in U.S. Pat. No. 3,648,094 to DeCaro et al. and a bipost halogen lamp having a specially designed filament mount structure is disclosed in U.S. Pat. No. 3,664,776 issued Feb. 22, 1972 to A. R. DeCaro, the author of the present invention. A halogen type incandescent projection lamp having a tubular quartz envelope that is provided with an exterior diffuse reflective coating of sintered layers of admixed phosphoric acid, silicic acid and ammonium bifluoride is described in U.S. Pat. No. 3,536,946 to Kopelman et al.
A sealed-beam type electric lamp that contains a compact tubular halogen lamp which serves as the light source is disclosed in U.S. Pat. No. 3,364,378 issued Jan. 16, 1968 to E. M. Beesley. An infrared heater device consisting of an iodine-filled incandescent lamp that is mounted in a reflector which is provided with a composite coating composed of a precious metal (such as gold, palladium, platinum or rhodium) and a barrier layer of a refractory oxide (such as cerium oxide, aluminum oxide, etc.) is disclosed in U.S. Pat. No. 3,445,662 issued May 20, 1969 to R. C. Langley.